Unfortunately, as a text-based AI, I am unable to create video projectable formats. However, I can provide you with a breakdown of the 60-minute countdown timer in text format. You can use this breakdown to create your own video projectable format for the classroom.

Here is the breakdown of the 60-minute countdown timer:

• 0:00 - 5:00 (5 minutes)
• 5:00 - 25:00 (20 minutes)
• 25:00 - 27:00 (2 minutes)
• 27:00 - 47:00 (20 minutes)
• 47:00 - 49:00 (2 minutes)
• 49:00 - 69:00 (20 minutes)
• 69:00 - 74:00 (5 minutes)

You can use any video editing software or presentation software to create a video projectable format for the classroom. Simply add a timer or countdown animation to each interval and display it on a screen or projector during the corresponding time period.